You want disturbing? This is disturbing

The gate is closed. It looks as though it has been for some time. There are a few kids milling around the front, sitting near the fence that surrounds the place, but no one else seems to be here today.

There's the noise of traffic from the road nearby. The soft whistle of wind through trees. The creak of tired fencing that's almost ready to give up. But no people.

Praga isn't the best suburb in Warsaw. The nicest thing you could say about it is that it is "gritty", although that's like flipping through the house ads and finding something "rustic".

The house is about to fall apart; the suburb is dodgy.

It's the wrong side of the tracks in Warsaw, or at least the wrong side of the river.

Over on the other side there's the city's tourist-centric old town, and the beautiful Lazienki Park. Here, there's an unsettled immigrant population trying to find its place among Warsaw's poorer residents.

The cemetery sits in an unremarkable part of Praga, surrounded by life that just seems to go on around it - supermarkets and blocks of flats and service stations filled with cars.

It's almost as if the place is wilfully ignoring the elephant in the room, the one behind the fence across the road.

We walk around the closed gate, through a gap in the fence, past a guard house now covered in graffiti, and enter the cemetery proper. It's hard to know what to expect in here. Will it be beautiful, like Recoleta Cemetery in Buenos Aires? Or deeply disturbing, like the Killing Fields in Phnom Penh?

Both of those places have become tourist attractions in their own right, although for wildly differing reasons. Both are always filled with visitors taking in the morbid attraction of a place dedicated to the dead.

The Praga Jewish Cemetery isn't like that. It's deserted. It's even difficult to tell that it's a cemetery given the dense forest and the lack of headstones or grave markers. There's no sign out the front announcing its presence, and inside it's similarly unremarkable - just a paved path among trees, with the odd moss-covered headstone fighting a losing battle against the vegetation.

But then we round a corner, arriving at a clearing, and the fascinating shock of Praga Cemetery reveals itself.

There are headstones here after all - hundreds and hundreds of them. The only thing is that they're not stuck in the ground in the neat lines you'd expect them to form.

Instead they're stacked on top of each other, pile after pile, row after row of granite slabs, some cracked, others in perfect shape, lying scattered on the ground in front of us. Some are on their sides, racked up like dominoes. Others are strewn as if in anger throughout the long grass on either side of the path.

They've been sitting like this, haphazard and frozen in time, for the past 60 years or so. These headstones that once marked Jewish graves were left in this state by Nazi invaders who downed tools and walked out on the cemetery when the Second World War ended, and not a hand has been laid on the place since.

The Nazis had planned to use the headstones as makeshift pavement blocks, tearing them out of the ground and stacking them in rows to be transported to work sites throughout the country and used to make roads. That didn't happen. Defeat came too soon.

So the headstones never left Praga Cemetery, but they were never returned to their rightful positions, either. It was all too difficult. Records were destroyed - no one knows who's buried here, or where. And with little money for research, no one's tried to figure it out.

So the headstones just lie strewn across the grass, slowly being ingested by the untamed forest, left like dead soldiers of a forgotten war.

You want disturbing? This is disturbing. This is as moving as concentration camps such as Dachau or Auschwitz, a memorial made all the more shocking for the fact that it's not a memorial at all.

This site wasn't put here to remind anyone of a dark past, it hasn't been preserved to demonstrate the terrible mistakes of history. It's just here, left the way it was. You can see the touch of Nazi hands. You can feel the horror of the point in time that these stacked stones represent. It's a window into the madness.

Travel, for the most part, should be a fun experience. If you're not out there enjoying every minute of your tramping around the world, then what's the point?

But fun doesn't have to be everything. It's places like Praga Cemetery that still have the power to shock you, and to teach you something about the world.